TSLP: A Biomarker Predictive of Atopic Dermatitis Development in Infants

Background
Atopic dermatitis (AD) is a chronic inflammatory skin disorder that affects nearly 17% of children and can persist into adulthood. Advances in understanding the mechanisms underlying AD require direct sampling of the skin. Because AD is primarily a skin disease involving infants and young children, there are no skin-based studies examining AD in this age group due to the invasiveness of skin biopsies. The abnormal skin barrier in patients with AD allows epicutaneous absorption of environmental allergens through the skin and promote systemic allergen sensitization, which predisposes to the development of other allergies such as food allergy and asthma.
AD is a complex disease with a genetic predisposition strongly influenced by innate and adaptive immune responses, as well as environmental factors, including allergen exposure, irritants, microbes, diet, stress, and air quality.
To establish a primary prevention strategy for AD, it is important to identify and predict the occurrence of AD. Current treatment approaches are not curative and they include use of strategies to improve skin barrier or downregulate the type 2 allergic immune response. This is why there is considerable interest in developing biomarkers that could predict AD.

Technology
Thymic stromal lymphopoietin (TSLP) is an epithelial cell-derived cytokine expressed in skin (keratinocytes), gut, and lungs. It has a critical role in driving Th2-mediated inflammation by modulating antigen-presenting cells to amplify Type 2 cytokines by T cells and innate lymphoid cells.
In a skin tape stripping study, Dr. Leung and his collaborators demonstrated that increased TSLP expression in the epidermis precedes the development of AD in infants as young as 2 months. Therefore TSLP may serve as an early biomarker for AD.

Potential Applications
TSLP-based diagnostic assay for early identification of infants predisposed to development of AD and predicting patients that will respond to treatment with a TSLP inhibiting agents.

State of Development
Additional skin tape stripping studies will be needed to validate biomarkers which predict infants at risk of developing AD in different racial groups.